IRGM and glioma: Previous studies show gliomas contain a plenty of macrophages, and tumor-associated macrophages correlate with progression and angiogenesis of gliomas by several ways, including: microRNA-macrophage feedback loop (Bao & Li, 2019; Liu et al., 2019), extracellular lipid loading (Offer et al., 2019) and cytokines like OPN, IRGM, IL-6 (Hernandez-SanMiguel et al., 2019; Wang et al., 2018; Xu et al., 2019).